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35 rub Reiseued Jan. 5, 1932 UNITED STATES p Re. 18,312

PATENT OFFICE GUSTAVUS J. ESSELIN, JR OF SWAMPSGOTT, MASSACHUSETTS, AND P. BOSE, OI! JACKSON HEIGHTS, NEW YORK, ASSIGNORS TO GENERAL RUBBER GOMPANY, NEW YORK, N. Y A CORPORATION OF NEW JERSEY COATED PAIPER Io Drawing. Original application illed March 19, 1924, Serial No. 700,428. Divided and this application filed April 8, 1926. Serial No. 21,700. Patent liq. 1,746,889, dated February reissue filed September 1, 1931. Serial No. 560,656.

should possess a surface which resists absorption of ink and-colors applied thereto. It should also resist wear and tear even after constant flexing. Heretofore coated papers have been made by applying to the surface of a suitable paper a m1xture of a finely divided mineral such as clay, blanc fixe, etc. with or without a pigment, together with an adhesive which ordinarily consists in large part of casein. Glue and starch have also been tried as adhesives, but casein has been the, material preferred. The coated papers heretofore made have, however, had surfaces whose resistance to ink absorption as well as their wearing qualities have been susceptible Papers heretofore produced have also been somewhat expensive due particularly to the use of casein as the binder.

The principal object of the present invention accordingly is to rovide a coated paper which shall have a higher resistance to ink absorption than papers heretofore produced,

. which shall be stronger and better able to withstand flexin in which there shall be good adhesion etween the coating and paper, and which shall be less expensive than previous coated paper.

The invention accordingly comprises paper coated with a mixture comprising berlatex and a filler material (usually finely" divided clay or other mineral or mixtures of materials) with or without other organic hinder or binders such as starch or casein.

In carrying out the invention in its preferred form, 25 lbs. of starch previously boiled 11pv with 20 gals. of water are carefully and thoroughly mixed with 100 lbs. of a finel divided clay. This mixture is pref crab y allowed to stand several hours before cautions mentioned heretofore.

11, 1980. Application for use. It is important that the clay be thoroughly dispersed. Latex containing say 1% of ammonia as a preservative in sufficient amount-to produce 1.25 lbs. of rubber solids is then carefully stirred into the mixture of starch and clay. The latex is thoroughly mixed with the mass of starchand clay and sufiicient'water is added .to obtain a consistency necessary for proper working on the particular type of coating-machine ,employed. This mixture is then applied to a web of paper in the usual manner. The paper so treated is dried and may be calendered or subjected to. other processes ordinarily employed in the production of coated paper. 1 I

The embodiment just given including latex and starch is referred among other reasons on account of its low cost. bimilar results have been obtained substituting glue in part or entirely for starch. An embodiment of the invention employing glue is as follows:'

ough mixing of the latexand other materials,

sufiicient' water is added to give a proper consistency for use with the particular type of coating machine employed. A web of paper is coated as mentioned in the last example, dried, calendered and otherwise treated in the usual manner to produce a coated paper.

Another example employin casein. is as follows: 10 lbs. of casein are dissolved in the usual manner with the help of 1 lb. of borax or suitable amounts of other alkali. The resulting solution is thoroughly mixed with llllllbs. of finely divided clay, with the presuflicient latex, containing 1% ammonia as a Thereaiter gals. of water containing 3 lbs. of borax.-

With this is carefully mixed 100 lbs. of finely -divided clay. To this mixture is carefully added suflicient latex containing approximately 1% ammonia as a preservative to produce 5 lbs. of rubber solids. The mixture so obtained is a plied in the usual manner to paper to pro uce a. coated paper.

be incorporated with the coating mixture or may be applied before, durin or after coating and vulcanization may carried out, preferably at temperatures below 200 F.

The appearance of the coated papers produced by the above processes is similiar to the appearance of other commercial coated papers, but their properties are quite different. The papers of the present invention resist absorptionef blotting of ink 5 to greater than other coated papers. In addition they are superior to the ordinary coated papers in resistance to wear. As an index to the increase in strength of paper the following data determined by the folding test was obtained on papers of equal weights:

Folding teat Number of times folded before tearing m Other components Not calendered Calendered Machine Crow Machine Cross None. Casein lbs. clay 100 lbs. Folded 13 times. Folded 5 times. Folded times. Folded 6 times. 1.25 lbs. Starch lbs., clay ll!) lbs. Folded 13 times. Folded 8 times. Folded 17 times. Folded 12 times. 2.51:. Casein 10 lbs., clay 100 lbs. Folded 22 times. Folded 6 times. Folded times. Folded 23 times. 6.25 lbs. Starch 12 lbs., clay lbs. Folded 52 times. Folded 18 times. Folded 59 times. Folded'21 times. 101m. (1313M ellac 10 lbs., clay 100 Folded 38 times. Folded 21 times. Folded 93 times. Folded 37.5 times.

be. 14 lbs. G]: 1% of rubber solids, clay 10o Folded 30.5 times. Folded 8 times. Folded 104 times. Folded M times.

It will be understood that other finely divided mineral substances than clay may be employed in the above procedures. For example we may use, to replace at least a portion of the clay, one or more of the following substances: Satin white which is largely a mixture of calcium sulphate and aluminum hydrate, blanc fixe which is largely barium sulphate, and Paris white which is largely calcium carbonate or other suitable materials.

Our experience in preparing coating mixtures including clay is that better results are obtained when the total quantity of'rubber solids plus other binder is present in amounts greater than 12% of the weight of the clay. his quantity of course will vary somewhat in accordance with the kind of clay employed and in case clay is substituted in whole or in part by other materials a. similar variation in the percentage of binder will occur.

It has been observed in mixtures of latex and starch as given in the preferred embodiment that the larger the proportion of latex used with respect to the starch the less total amount of binder is required togive a satisfactory product. For example a mixture con taining 12% starch and 6.25% rubber solids based on the weight of the clay gives a somewhat more satis actory product than a mixture containing 20% of starch and only 2% of rubber solids.

Other preservatives than ammonia may be used.

dedred, material for vulcanization may The above folding data was obtained acper machine.

Another important characteristic of coated papers is that the coating material shall adhere firmly to the paper.. Coatings employing casein alone have good adherence to the paper with which they are employed and it has been found that the coatings of the present invention adhere as well or better than the casein coatings heretofore used. In addition it has been found that the coated papers of the present invention are less expensive to manufacture than those heretofore prepared. For example papers employing starch and latex manufactured according to the preferred example above are reduced at a cost of somewhat less than onealf that required for the production of good caseincoated paper.

As many apparently widely different embodiments of this invention may be made without departing from the spirit thereof, it will be understood that we do not intend to limit ourselves to the specific embodiments herein set forth except as indicated in the appended claims.

Having thus described our invention, what we claim and desire to protect by Letters Patent is: v

1. A coated paper consisting of paper coatcording to standard procedure on a Schoped with a mixture of rubber latex and filling V material including a shellac product and a dispersing agent therefor.

2. A coated paper consisting of paper :coated with a mixture of rubber latex and filling material-including a borated shellac.

3. A coated paper consisting of aper coated with a mixture comprising ru ber latex, clay, and shellac treated with borax.

4. A coated paper consisting of paper coated with a mixture comprising a major proportion of clay, and rubber solids of latex and borated shellac in minor proportion.

5. A coated paper consisting of paper coated with a mixture comprising clay, rubber solids of latex, an adhesive from the group consisting of borated shellac, casein, starch and glue, the clay being in proportion greater than an other ingredient, and the rubber solidso latex and adhesive being in minor proportion of the composition.

6. A coated paper consisting of paper coated with clay, rubber solids of latex, and an adhesive fromthe group consisting of borated shellac, casein and starch, in propor- 7 tions by weight of approximately 1.25 to 10 parts rubber solids of latex, and 10 to 25 parts said adhesive, to 100 parts clay.

7. A coated paper consisting of paper coated with mineral fillermaterial containing clay, at least a portion of which is replaceable with one or more of the substances, satin white, blanc fixe, and Paris white, rubber solids of latex, and an adhesive from the group consisting of borated shellac, casein, and starch, in proportions by weight of approximately 1.25 to 10 parts rubber solids of latex, and 10 to 25 parts said adhesive, to 100 parts mineral filler material.

8. A coated paper consisting of paper coated with a mixture comprising a major proportion of mineral filler material containing 1 1. A coated paper consisting of paper coated with a mixture of at least 7 5 per cent clay by weight and including rubber solids of latex and an adhesive in minor proportion.

12. A coated paper consisting of paper coated with a mixture comprising a. major proportion of clay and a minor proportion of rubber solids of latex and adhesive.

Signed at Boston, in the county of Suffolk, and State of Massachusetts, this 18th day of August, 1931.

GUSTAVUS J. ESSELEN, J'R. Signed at New York, in the county and State of New York, this 6th day of August,

REED P. ROSE.

clay, at least a portion of which is replaceable with one or more of the substances, satin white, blanc fixe and Paris white, a minor proportion of rubber solids of latex, and an adhesive from the group consisting of borated shellac, casein and starch in the proportion of 10 to 25 parts said adhesive to 100 parts said mineral filler material.

9. A coated paper consisting of paper coated with a mixture comprising a major proportion of clay, and rubber solids of latex and an adhesive, the rubber solids of latex. and adhesive being in minor proportion and in amount greater than 12% of the weight of the cla 10. coated paper consisting of paper coated with a mixture comprising a ma or proportion of mineral filler material containing clay, at least a portion of which is replaceable with one or more of the substances satin white, blanc fixe, and Paris white, an

' rubber solids of latex and adhesive, the rubher solids of latex and adhesive being in minor proportion and in amount greater than 12% o terial.

the weight of the mineral filler ma- 

